Hybrid vehicles have become increasingly popular in recent years. This is due to many factors such as, for example, the relative efficiency of hybrid vehicles, the rising cost of energy and an increased desire in society for more environmentally friendly modes of transportation.
Hybrid vehicles typically have a gasoline or diesel powered engine and an electric powered engine. The electric powered engine is powered by one or more batteries. Generally, instead of charging the battery via an electrical outlet, surplus energy from operation of the hybrid vehicle is used to charge the battery via a generator powered by the surplus energy. Surplus energy may be obtained, for example, during use of the gasoline powered engine, during breaking or slowing down of the hybrid vehicle, or when the hybrid vehicle is travelling downhill. Hybrid vehicles may operate in a gasoline engine-only mode, an electric engine-only mode, and a mix of the two modes, wherein the proportionality of the gasoline engine and the electric engine may vary. Those skilled in the art will understand that some hybrid vehicles utilize other types of engines, as opposed to an electric engine, in combination with the typical gasoline or diesel engine, and thus, other forms of energy storage in place of batteries. For example, compressed air is an emerging option to replace batteries. A pneumatic engine and compressor combination may replace the electric engine and generator combination, where the compressor is powered by surplus energy. Thus, as used herein, the term “electrical power” includes other forms of alternative power.
Currently, batteries for hybrid vehicles are generally maintained at a “steady state” charge of 70% of capacity, for example. This allows for recharging of the battery when the hybrid vehicle slows down or drives downhill since it is not at 100% of capacity. Conversely, with a steady state charge of 70% the battery may also have sufficient capacity to supply energy in order to, for example, accelerate the car, or to power up a short incline. Although steady state charging to 70% capacity may provide a suitable default for many conditions, it may be more efficient in some conditions to charge the battery to different levels in order to enable an improved utilization of the electrical powered engine, reduction of battery requirements and the like.